1. Field of the Invention
The present invention relates to a switch assembly for sensing the position of relatively pivoted members that accommodates limited non-pivoted movement of the members.
2. Background Art
It is well known to use switches to sense movement of articulated members. For example, linkages may be provided with switches that indicate the position of links relative to each other and supporting structures. Switches may comprise limit switches, reed switches, Hall Effect sensors, and the like. Signals from such switches are processed by control systems that may control linkage drive systems or coordinate movement of the linkage with other systems.
Examples of linkages that have switches may include convertible top stack linkages and retractable hard top systems but may also include a wide range of other types of linkages. Convertible top stack linkages are made up of a plurality of bows that are connected by links that are used to fold the convertible top between an extended position and a retracted position. Retractable hard tops have rigid panels that are linked together and may be moved between an extended position and a retracted position.
Switches on convertible tops and retractable hard tops may be used to sense the location of the top and provide signals to a controller. The controller may be used to start, stop and control movement of the top and also may be used to sequence operation of the top stack linkage with a power operated tonneau cover.
A pivot normally has only one degree of freedom in that it permits two parts of a linkage to pivot relative to each other. Linkages with only one degree of freedom may become misaligned relative to adjacent structures. If a linkage is misaligned it may not be able to move to a desired position. A pivot may be provided with an additional degree of freedom by various mechanisms that permit movement other than a pivoting movement. If a pivot is provided with an additional degree of freedom, a switch that senses the position of links connected at the pivot may provide an inaccurate representation of the sensed position of the links.
In the specific case of a rear bow of a convertible top, the five bow is normally at the bottom of the stack when the top is stored in the storage well. The top cover may become pinched between stacked bows that exert pressure on the top cover to compress it for storage. A lost motion connection can increase the freedom of the top to be better aligned with the storage well.
In addition, with a convertible top or retractable hard top, a lower rear edge of the top must be able to engage the vehicle at the belt line. A good fit should be formed where the lower rear edge of the top contacts the vehicle body. Due to manufacturing variation and tolerance stack up, the rear most bow of a convertible top or rear edge of a retractable hard top may be out of alignment with the contact line on the vehicle body that they are intended to engage. If there is an offset in the position of the linkage and vehicle body contact line either side to side or as the relative height, a gap may be formed between the top and the vehicle body. To eliminate any such gap, a lost motion connection may be provided in the pivot that can provide an additional degree of freedom that allows the linkage to align itself with the vehicle body. A problem arises with such lost motion connections if the position of the pivoted links is monitored by a conventional switch arrangement.
There is a need for a switch that can cooperate with a pivot connection having a second degree of freedom that permits self-aligning or equalizing of the location of the pivoted links relative to adjacent structure without adversely impacting switch performance. Stated in other terms, there is a need for a switch assembly that provides accurate sensing of the location of pivoted links that have a lost motion connection. These needs and others are addressed by applicant's invention as summarized below.